Rail grade selection and friction management: a combined approach for optimising rail–wheel contact

Abstract

To investigate the mechanisms behind rolling contact fatigue (RCF) and wear, a collaborative test program was conducted by voestalpine Schienen GmbH (Leoben, Austria) and Kelsan Technologies Corp. (a part of LB Foster Friction Management) on the full scale test rig of voestalpine. A reference grade was compared to a series of pearlitic rail grades under dry and friction modifier (FM) contact conditions. Rail and wheel profiles were collected at predefined intervals, allowing the calculation of wear rates. The initiation and development of RCF cracks were monitored using optical means and magnetic particle inspection. Metallographic sectioning of the samples was conducted to characterise crack growth and crack orientation as well as the evolution of surface and subsurface material flow. Additionally, the test rig results were compared to the results obtained from the extensive track test network of voestalpine and Kelsan to outline similarities and differences between test rig conditions and the conditions in track. The combination of rail grade, FM application and an appropriate maintenance strategy is seen to have a significant effect on the development and propagation of wear and RCF. This offers a huge potential for reducing the track LCC costs for the infrastructure owners.